How I'm thinking about our house, transportation, food and waste, to minimize environmental impact, while improving quality of life and having fun.

September 2011

09/12/2011

Martha's Vineyard got off really easy in Irene, compared to what mightabeen. We lost power here for a few hours - no tragedy, to be sure, but it got me thinking again about what if we were out for days, and how frustrating it would be to have almost 5 kW of PV doing nada when the grid goes down. Grid-tied inverters look for the 60 Hertz signal from the grid to operate.

Asking around, I learned that the company that makes the inverter we used, SMA, makes an off-grid inverter called Sunny Island that can be configured to communicate with the grid-tied inverter, and working off of a small battery bank could provide power during the day and a modest amount (from the batteries) at night. I'm looking into what this will cost - it ain't cheap!

I continue to be amazed at the power generated on poor weather days. Tuesday last week it rained all day and Wednesday it was overcast with some drizzle. We received 2.5 kWh and 4 kWh on those two days. That's 6.5 kWh on two days where we used 10.5 kWh in total!